Ingition coil



ct. 14, 1941. W SCHWARZMANN 2,259,229

I IGNITION COIL Filed Feb. l, 1941 ATQRNEY mechanically fastened Patented Oct. 14, 1941 IGNITION con.

Wolfgang E. Schwarzmann, assigner to American Longmeadow, Mass.,r Bosch Corporation,

Springfield, Mass., a corporation of New York Application February 1, 1941, Serial No. 377,001 9 Claims. (Cl. 171-209) The present invention relates to low tension and high tension ignition coils for magnetos. battery ignition systems and other ignition generators, and particularly to such coils of stationary types having magnetic cores.y

s More specifically, as disclosed in the preferred embodiments hereinafter described.A the invention relates to an ignition coil or generating winding having one or more terminals to which an outside wire, such as that leading to the mechanical interruptor of thegenerator, is electrically connected by means of an insulated or live terminal connector` comprising a metal strip which is electrically connected to both a terminal post for the outside wire and a conducting member forl the terminals of the winding and which is to but electrically insulated from the magnetic core of the winding.

The primary' object of the invention is to provide a construction in which the electrical connections to the metal strip are relieved of permanent magnets 6. The two upper pole pieces mechanical strainsimposed on them, as byAre- I peated connection and disconnection of the outside wire to the terminal post, and also in ,which the connections are precluded as a practical matter from strains and crystallization resulting from continuous or severe vibration communicated to them in service particularly on airplanes. Thus the original effectiveness of such connections, even though formed by soldered joints, l

preserved in normal service over extended l periods, and the disastrous result that may occur in night from an accidental loss ofignition from this cause is practically obviated.

Another object is to simplify the construction and arrangement by fastening the insulated or live terminal connector of the Winding to its magnetic core by the same means as fastens the core in place across the pole shoe projections in magnetic contact therewith.

Another object is to provide an ignition coil having means in or associated with the aforesaid terminal connector for improving the result of its impregnation by preventing the loss of impregnating material from the coil at the place or places of bringing out terminals from it.

Still another object is to provide, as elements for replacement or otherwise in ignition generators, unitary ignition coils with the terminal connectors and other features herein disclosed.

Further features and advantages of the in- Y vention will be understood from the following disclosures taken in connection with the accompanying drawing showing, as examples, high tension ignition coils of stationary and impregnated types for magnetos. In the drawing:

Fig. 1 is a vertical cross section, partly in elevation, of a magneto showing an ignition coil in position therein; Fig. 2 is -an end elevatio-n of the coil, partly in section, showing one embodiend of the coil.

5have upstanding integral arms or projections 'l providing supports for the stationary high tension ignition coil generally indicated by 8 and having primary and secondary generating windings. vThis coil has fastened in it a laminated magnetic core 9 the projecting ends of which are mechanically held across the arms I in magnetic contact therewith by screws I0, I I extending loosely through the core into screwthreaded engagement with the arms.

In the embodiment of the terminal connector of Figs. 2 and 3, the ignition coil has an outer secondary winding with its outer terminal electrically connected to the high tension terminal I2 and its inner terminal electrically connected to the outer terminal of the primary winding, as is well known in the art. The grounded inner terminal of the primary winding is drawn through a hole I3 in the core 9, and the live outer terminal thereof and the inner terminal of the secondary Winding are drawn through the two holes I Il in the insulating end disc I5 at the other After vacuum treatment and impregnation of the coil, as hereinafter described, the hole I3 is closed and the terminal electrically tightly by a tinned-over brass plate or conducting member I 6 and the terminals electrically connected t0 the member and to each other by soldering them to its outer face after pulling them through holes registering respectively with the holes I4. This member I6 has a projecting arm I1 which, out of the plane of the member, is bent around and soldered to a metal strip I8 formed of thin, hard or half-hard, and fiat tinned-over brass, riveted to the terminal post I9 in electrical connection with both the member and the post. The strip has an enlarged intermediate part 20 witha hole at 2| in line with the slot at 22 at that end of core 9. The post I9 has a hole at 23 for receiving the terminal of wire 24, which leads to the live terminal of tightly clamp the wire terminal in the hole and through the strip I8 the electrical connection ci the post to the conducting member i6 and the coil terminals soldered thereto.

The screw I passes directly through a slot at one end of core S to mechanically and electrically fasten the core at that end to one of the upv standing arms l. The screw il passes through the slot 22 at the other end of the core, but is insulated from strip i8 by the insulating washer 2 and insulating bushing 28. Thus the inner terminal o the primary winding soldered in the hole i3 of the core S is grounded on the magneto frame, while the other or live primary terminal, together with the inner terminal of the high tension winding, are electrically connected to the conducting member i@ and thence through the strip i8 to terminal post le. but are insulated from the core 9. However, the screw ii fastens the strip i8 mechanically to the core so that the strip supports the terminal post ES, with the wire 2d fastened thereto, from the core with little or no mechanical strain on the conducting member lo or the soldered connections of the coil terminals thereto.

It will be observed from the foregoing that the insulated terminal connector (comprising the conducting member I6 stuck or otherwise arranged on the outside face of the end disc i5, the metal strip i8 and the terminal post i9) has no part extending to the inside face ofthe end disc i where it might bring about a short circuit or electrical break-down of the coil. Also, it will be understood that the exibility of the metal strip i8, which may result from the form or character of its connection with the conducting member i6 through the projecting arm il thereof, or inherently from its structure including its dimensions and form, permits the strip to be drawn down rigidly into mechanical connection with the core 9 without imposing any substantial mechanical strain on the soldered joints between the member it and the terminals of the primary and secondary windings of the coil. Furthermore, the pull at the post i9, particularly upon connecting and disconnecting the wire 2d there= to, is prevented to a substantial degree from being transmitted to those soldered joints as a. result of the support of the post afforded by the core 9. and likewise for the strains and crystallization eiects from substantially all vibration set up in the magneto in service. In this way the original eiectiveness of these soldered joints is maintained over an extended period of service, and the continuity o ignition thereby made more reliable. Y,

In the embodiment of Figs. 4 and 5, the construction is the same except that the metal strip 3@ is mechanically fastened at its outer end 3i, instead of at an intermediate place, to the core 9. However, the terminal post 32 is supported substantially solely by the core, and as beore substantially no mechanical strain or vibration is i transmitted by the strip to the soldered connections between the metal member 33 and the terminals of the primaryand secondary windings.

in both embodimntgthe. coil d is subjected to vacuum treatment and impregnation. For this purpose the primary and secondary windings, with their terminals extending loosely through respective holes i3 and ld, and with the core in place, are subjected to exhausting apparatus to withdraw from the coil substantially all moisture, air, etc. and, while in this condition, oil or other impregnating insulating material is forced into the coil to ll substantially all its interstices in accordance with well known pracvconnection therewith,

tice. the hole i3 is sealed by soldering the grounded terminal therein, and the conducting member I6 is stuck or otherwise arranged on the end disc i5 with the terminals extending through the -holesin the conducting member registering with the holes i4. The holes in the conducting member are then sealed by owing solder over it as indicated to ill the holes and to electrically connect the live terminal of the primary winding and the inner terminal of the secondary winding of the coil to the conducting member i6 and to each other. In this way, no leakage of impregnating material from the coil can occur through the holes in the conducting member i6 or through the hole, i3 in core 9, notwithstanding repeated heating and cooling periods of the magneto in service.

It will be understood that windings, whether or not impregnated, its magnetic core, end discs and itsinsulated terminal connector having means for mechanical connection to the core, form a unitary element. Such an element may be installed as an original part of the ignition generator or may be provided as a spare element for replacement therein.

While but two embodiments of the invention are disclosed, it will be understood that many changes therein and variations thereof may be made and many other applications may be devised. For instance the invention may also be applied to coils with cores for use in battery f ignition systems and other ignition generators, whether s uch coils have inside or outside secondary windings in which one or both terminals are insulated and whether they have primary windings in which one or both terminals are insulated. Such and other changes, variations and other applications are intended to be included within the broad scope of the appended claims.`

Having thus described the invention, what is claimed is: v

l. In an ignition generator having pole piece projections; a'stationary generating winding; a magnetic core 'for said winding; an insulated terminal connector for said winding comprising a conducting member having an electric connection with a terminal of said winding, a terminal post having fastening means for fastening an outside wire in electrical connection therewith, and `a metal strip mechanically fastened to said member and post in electrical connection with both of them; and fastening means which mechanically fastens said strip to said core and electrically insulates them and which also fastens said core across said pole piece projections in magnetic contact therewith.

2. In a high tension ignition generator having pole piece projections; a stationary coil having primary and secondarywindings; an insulating end disc for saidcoil having holes through which extend terminals of said primary outside of said disc and having holes which register with the holes in said disc andthrough which said terminals extend, means for electrically connecting said terminals to said member and to each other, a terminal post having fastening means for fastening an outside wire in electrical and a metal strip mechanically fastened to said member and post in electrical connection with both of them; and

Upon removal of the impregnated coil,

the con with its y fastening means which mechanically fastens said strip to said core and electrically insulates them and which also fastens said core across said pole piece projections in magnetic contact therewith.

3. In an ignition generator having pole piece projections; a stationary impregnated generating winding; an insulating end disc for said winding having a hole'through which a live terminal of said winding extends; a magnetic core for said winding having a hole into which extends a grounded terminal of said winding; an insulated terminal connector for said winding comprising a conducting member arranged on the outside face of said disc with a registering 4hole through which said live terminal extends, a terminal post having fastening means for fastening an outside wire in electrical connection therewith, and a metal strip mechanically fastened tosaid member and post in electrical connection with both of them, said hole in said core and said hole in said member being sealed so as to prevent leakage of impregnating material from said winding therethrough and to electrically connect said grounded and live terminals to said core and member respectively; and fastening means core passing through said coil and seated on said which mechanically fastens said strip to said core and electrically insulates them and which also fastens said core across said pole piece projections in magnetic contact therewith.

4. In an ignition generator having pole piece projections; a stationary generating winding; a magnetic core for said winding; an insulated terminal connector for said winding comprising a conducting member having an electric connection with a terminal of said winding, a terminal post having fastening means for fastening an outside wire in electrical connection therewith, and a metal strip mechanically fastened at one end to said member and at its other end to said post in electrical connection with both of them; and fastening means which mechanically fastens said strip to said core intermediate of said member and post and electrically insulates said strip and core and which also fastens said core across said pole piece projections in magnetic contact therewith.

5. In an ignition generator having pole piece projections; a stationary generating winding; a magnetic core for said Winding; an insulated terminal connector for said winding comprising a conducting member having an electric connection with a terminal of said winding, a terminal post having fastening means for fastening an outside wire in electrical connection therewith, and a metal strip fastened at one end to said member and intermediate of its length to said post in electrical connection with both of them; and fastening means which mechanically fastens said strip near its other end to said core and electrically insulates them and which also fastens said core across said pole piece projections in magnetic contact therewith.

6. In an ignition generator having pole piece projections; a stationary generating winding; a magnetic core for Isaid winding; an insulated terminal connector for said winding comprising a conducting member having an electric connection with a terminal of said winding, a terminal post having fastening means for fastening an outside wire in electrical connection therewith. and a metal strip mechanically fastened t0 slid member and post in electrical connection with arms; means for electrically connecting a grounded terminal of said primary winding to said core; an insulated terminal connector for said coil comprising a conducting member having an electric connection with terminals of said primary and secondary windings, a terminal post having fastening means for fastening an outside wire in electrical connection therewith, and a metal strip fastened to said member and terminal post in electrical connection with both of them; fastening means for mechanically and electrically connecting one end of said core to one of said arms; and other fastening means for mechanically fastening the other end of said core to the other of said arms and for mechanically fastening but electrically insulating said strip and core.

8. As a unitary element for a high tension igni tion generator; a coil having primary and secondary windings; a magnetic core`extending through said coil and being electrically connected to a grounded terminal of said primary winding; and an insulated terminal connector comprising a conducting member electrically connected to a live terminal of said primary winding and t0 a terminal of said secondary winding, a terminal post having fastening means for fastening an outside wire in electrical connection therewith, and a metal strip fastened to said member and post in electrical connection with both of them, said strip having a hole arranged for the passage of a screw and insulating member to mechanically fasten said strip to said core.

9. As a unitary element for a high tension ignition generator; a coil having impregnated primary and secondary windings; an insulating end disc having holes through which extend a live terminal of said primary winding and a terminal of said secondary winding; a magnetic core for said coil having a hole into which extends a' grounded terminal of said primary winding; and an insulated terminal connector comprising a conducting member lon the outside face of said disc and having holes which register with the holes in said disc and through which extend the terminals therein, a terminal post having fastening means for fastening an outside -wire in electrical connection therewith, and a metal strip which is mechanically fastened to said member and post in electrical connection with both of them and which has a hole arranged for the passage of a screw and insulating member to mechanically fasten said strip to said core, said holes in said core and member being sealed in such manner as to prevent leakage of impregnating material from said core therethrough and toelectrically connect the terminals therein.

WOLFGANG E. SCHWARZMANN. 

